Computer virtualization is a technique that involves encapsulating a representation of a physical computing machine platform into a virtual machine (VM) that is executed under the control of virtualization software running on hardware computing platforms (also referred to herein as “host computing systems” or “servers”). A group of hardware computing platforms may be organized as a cluster to provide hardware resources, such as memory, central processing units (CPUs) and so on, for VMs. Each VM is a complete execution environment, and the server provides a user interface over the network connection so that user inputs and outputs are communicated between the user and the VM.
Further, host computing systems may be attached with one or more peripheral devices such as input devices (e.g., a keyboard, a mouse, a graphic tablet, a touch screen, an image scanner, a microphone, a webcam, and a barcode reader), output devices (e.g., a display device, a printer, and a graphical output device), storage devices (e.g., an external hard drive, a flash drive/solid-state drive, a disk drive commonly within a hard drive enclosure, a smartphone or tablet computer storage interface, a CD-ROM drive, and a DVD-ROM drive) and input and output devices (e.g., a modem and a network interface controller). Each such peripheral device requires some host computing system resources, such as processor (CPU) time, input/output (I/O) bandwidth on the various data buses, and physical memory space.
Furthermore, different generations of host computing systems can have different types of peripheral devices. Typically, when a peripheral device is attached to a first host computing system, the peripheral device is available only to VMs that run on the first host computing system and may not connect to VMs that run on other host computing systems in the datacenter.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present subject matter in any way.